1. Field
The following description relates to a balun, and more particularly, to a balun including a film bulk acoustic resonator (FBAR) that may convert a balanced signal into an unbalanced signal, and/or convert an unbalanced signal into a balanced signal.
2. Description of Related Art
A balun may be used as a circuit/structure that may convert balanced signals into unbalanced signals or unbalanced signals into balanced signals. The balun may include a passive element that may operate even when an input and an output are reversed.
A conventional balun is fabricated to include a plurality of transistors, or using a wavelength of a signal on a single plane. The conventional balun is a part of a parallel type circuit such as a mixer, an amplifier, a multiplier, a phase shifter, and the like, and is generally implemented using a Lange coupler or an interdigital coupling.
However, the size of the balun using the wavelength of the signal plane may be significantly great. Also, a balun including a plurality of transistors may have a large difference between two outputs, and a supplementary circuit may need to be inserted in the balun to correct the difference between outputs. In addition, the power consumption of the conventional balun is relatively great due to the plurality of transistors, and the yield of the circuit may be reduced by such power consumption. Accordingly, these two types of baluns may cause a reduction in a degree of integration of a semiconductor, and therefore may not be readily implemented in an integrated circuit.